Manufacture of microchip devices continually strives for smaller sized elements for higher density integrated circuit design on a target wafer. For example, demand for 20 nm resolution now exists for features of logic circuits and arrays in microchip fabrication. Wafer inspection systems can detect defects that occur during the manufacturing process. Inspection and metrology of wafer dies may utilize a scanning device such as a scanning electron-beam microscope (SEM) to generate die images for die-to-die comparisons based on measurements of die features. However, images from the scanning device may include noise that can interfere with accurate determination of contour lines for the die features from which measurements are taken. Extraction of feature edges is unreliable for determination of the contour lines, as there may be false contour lines identified due to noise.